* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}


body {

    background: #050505;

    color: white;

    font-family:
        Arial,
        Helvetica,
        sans-serif;

    min-height: 100vh;

    overflow: hidden;

}




.top-bar {

    position: fixed;

    top: 0;
    left: 0;

    width: 100%;

    height: 70px;

    padding: 0 30px;

    display: flex;

    align-items: center;

    justify-content: space-between;

    z-index: 100;

}


.back {

    color: #777;

    text-decoration: none;

    font-size: 12px;

    letter-spacing: 2px;

}


.book-name {

    position: absolute;

    left: 50%;

    transform: translateX(-50%);

    font-size: 14px;

    letter-spacing: 2px;

}


.hint {

    color: #777;

    font-size: 10px;

    letter-spacing: 2px;

}



.book-stage {

    width: 100vw;

    height: 100vh;

    display: flex;

    justify-content: center;

    align-items: center;

}




.page-control {

    display: none;

}




.book {

    position: relative;

    width: 430px;

    height: 600px;

    perspective: 2200px;

}



.sheet {

    position: absolute;

    width: 100%;

    height: 100%;

    top: 0;

    left: 0;

    transform-origin: left center;

    transform-style: preserve-3d;

    transition:
        transform 1s
        cubic-bezier(.65, 0, .35, 1);

}



/*
第一页最上面
*/

.sheet1 {
    z-index: 3;
}


.sheet2 {
    z-index: 2;
}


.sheet3 {
    z-index: 1;
}



.page {

    position: absolute;

    width: 100%;

    height: 100%;

    top: 0;

    left: 0;

    background: #e6ddc9;

    backface-visibility: hidden;

    overflow: hidden;

    box-shadow:
        0 10px 40px
        rgba(0, 0, 0, .45);

}




.front {

    transform:
        rotateY(0deg);

}




.back {

    transform:
        rotateY(180deg);

}



.page img {

    width: 100%;

    height: 100%;

    display: block;

    object-fit: cover;

}




.next,
.prev {

    position: absolute;

    bottom: 25px;

    width: 45px;

    height: 45px;

    border-radius: 50%;

    border:
        1px solid
        rgba(255,255,255,.45);

    background:
        rgba(0,0,0,.45);

    color: white;

    display: flex;

    justify-content: center;

    align-items: center;

    cursor: pointer;

    font-size: 18px;

    transition: .3s;

}


.next {

    right: 25px;

}


.prev {

    left: 25px;

}


.next:hover,
.prev:hover {

    background: white;

    color: black;

}



#flip1:checked
~ .book
.sheet1 {

    transform:
        rotateY(-180deg);

    z-index: 1;

}



#flip2:checked
~ .book
.sheet2 {

    transform:
        rotateY(-180deg);

    z-index: 2;

}


#flip3:checked
~ .book
.sheet3 {

    transform:
        rotateY(-180deg);

    z-index: 3;

}